1. Field of the Invention
The present invention relates to an LED (Light Emitting Diode) driver circuit and, more particularly, to an LED driver circuit capable of effectively reducing total current harmonic distortion of an LED module.
2. Description of Related Art
According to estimation from International Energy Agency (IEA), 19% of the electric energy in the world is consumed for illumination. As such, recently, numerous countries in the world are devoted themselves to replacing the low-efficiency incandescent lamp with high-efficiency light illuminating source. Accompanied by continuous and fast progress of the LED in luminous output and light-illuminating efficiency, the average cost for the light output of each lumen is decreased gradually. Therefore, illumination using the LED is becoming an important project for energy saving.
Currently, the industry has developed an AC LED suitably for use with AC power. The AC LED may directly use the AC power provided by the utility power, which has effectively overcome the problem of incapability of directly applying the LED in the AC power. However, there still has been an issue of improvement in manufacturing the AC LED. According to a general standard for illumination, the power factor of an LED lamp has to be above 0.9; the test value of the power factor needs to be above 95% of the nominal value; the total input power needs to be within 10% of the nominal value provided by a maker; and the current total harmonic distortion should not be above 33%. Thus, if the total input current harmonic distortion of an LED driver circuit is too high, the LED lamp will not be accepted by the standard, rendering it not advantageous in production. Therefore, it is desirable to provide an improved LED driver circuit to mitigate and/or obviate the aforementioned problems.